NAIROBI, Kenya — Tribal lines are being drawn over who won Kenya’s presidential election. But unlike the bloody violence that scarred the country five years ago, this time the only fighting is online.

Machete strikes and bows and arrows are being replaced by bitter Tweets and angry status updates.

The exchange of barbs between supporters of Deputy Prime Minister Uhuru Kenyatta — who was named the winner of the March 4 election with 50.07 percent of the vote — and his closest competitor, Prime Minister Raila Odinga, has degenerated into expletive-filled fights in social media that have the government worried.

The Ministry of Information and Communications said this week that it has been unable to contain “the ugly messages of hate and negative ethnicity” online. It said many of the messages qualify as hate speech.

Some officials worry that the virtual feuding could trigger real-life fighting.

“The outrage is becoming wider and the tension is palpable. It’s going to erode all our efforts of building national cohesion,” Milly Lwanga, vice chair of the government-funded National Cohesion and Integration Commission, told The Associated Press Thursday. “The buildup of tension, it’s like a room where gas is leaking slowly and then eventually there will be something small to ignite it and people will wonder where the explosion came from.”

After Kenya’s disputed presidential vote in late 2007, Odinga’s supporters took to the streets. Tribal violence erupted, resulting in the deaths of more than 1,000 people.

Odinga’s camp on Thursday said the prime minister will file a petition with the Supreme Court today to overturn the election results. Odinga alleges the election was rigged.

“We are dealing with criminals who should not be in State House but in prison,” said Odinga on Thursday of his opponents. But, significantly, he is urging his supporters to stay calm as his case is heard in court.

No major violence has been reported, but the interactions are ugly online. Ethnic allegiances are exposed and ridiculed. Kenyatta’s tribe — the Kikuyus — and Odinga’s tribe — the Luos — clashed violently five years ago, now they insult each other via the internet.